Tire pressure monitoring device with LED warning light turned on by mechanical pressure switch

Abstract

A tire pressure-monitoring device (TPMD) directly mounted onto an air-pumping inlet-stem on a tire. The TPMD includes a light emitter connected to a battery through an electrical connecting loop wherein the electrical connecting loop comprising a plurality of electrical conductive structural components and at least two of the structural components are physically separated in a normal tire pressure condition and connected in a low pressure tire pressure condition for providing power to the light emitter for emitting a low tire pressure warning light.

1. A tire pressure-monitoring device (TPMD) having a base cylindrical housing for directly screwing onto an air-pumping inlet-stem on a tire comprising:
 a tire-pressure engaging-member formed with a central membrane attached onto a base attachment ring wherein said central membrane is formed to directly engage to an air pressure pushing up through said air-pumping inlet-stem from an air filled in said tire wherein said tire-pressure engaging-member is formed as a replaceable single piece to separately place into the base cylindrical housing; 
 an upper cover assembly comprising a receiving cup having a sticking out extension configured to engage the central membrane wherein said receiving cup is engaged to a push down spring surrounded by a press-down ring screwed onto an insulation ring of the upper cover assembly; and 
 said upper cover assembly is formed as a separate piece to screw onto the base cylindrical housing for engaging and pushing down the central membrane onto the air-pumping inlet stem for engaging and detecting a tire pressure of the air filled in said tire. 
 
     
     
       2. The TPMD of  claim 1  wherein:
 said upper cover assembly includes a printed circuit board (PCB) supports a light emitting diode (LED) on a top surface wherein said LED is electrically connected to a battery through electrodes disposed on a bottom surface of said PCB directly contacting at least a battery electrode of a battery disposed below the PCB and wherein said PCB further includes an external current limiting resistor electrically connected to said LED as part of an electrical current loop for limiting a current to the LED; and 
 said pressure membrane pushes up the receiving cup to break said electrical current loop to said LED in a normal tire pressure for turning off said LED and the push down spring engaged to said receiving cup pushing down said pressure membrane for closing said electrical connection loop in a low tire pressure condition to turn on said LED to emit a low pressure warning light. 
 
     
     
       3. The TPMD of  claim 2  wherein:
 the battery includes a positive electrode to directly contact the electrodes disposed on the bottom surface of the PCB for connecting and providing electric power to said LED; and 
 said upper cover assembly having a transparent top cover for covering and protecting said LED and said PCB powered by said battery for transmitting said low pressure warning light therethrough. 
 
     
     
       4. The TPMD of  claim 1  wherein:
 said base cylinder housing having inner screws for screwing onto said tire-pressure inlet-stem and said base cylinder housing constituting a part of said electrical current loop. 
 
     
     
       5. The TPMD of  claim 4  further comprising:
 a spring adjust screw mounted on an insulation ring mounted inside said upper cover assembly and engaged to said push down spring for adjusting a push-down pressure pressing against said receiving cup. 
 
     
     
       6. The TPMD of  claim 1  wherein:
 said press-down ring mounting on and engaging to said base-attachment ring surrounding said central membrane and screwing onto inner screws of a said base cylinder housing for attaching said upper cover assembly as a separate piece to said base cylinder housing. 
 
     
     
       7. The TPMD of  claim 5  wherein:
 said insulation ring further includes outer screws for screwing onto inner screws of said receiving cup inside said upper cover assembly having a fixed range of up-down movement freedom depending on a pressure changes of said tire pressure. 
 
     
     
       8. The TPMD of  claim 2  wherein:
 said LED further comprises a conductive spring plate to engage to the battery. 
 
     
     
       9. The TPMD of  claim 8  wherein:
 said upper cover assembly comprises a top cover having a cylindrical hollow space for containing said battery, said printed circuit board and said LED in said cylindrical hollow space and said top cover further having outer screws for screwing onto inner screws of a base cylinder housing for assembling and containing said TPMD inside an integrated container housing formed by said top cover and said base cylinder housing. 
 
     
     
       10. The TPMD of  claim 9  wherein:
 said upper cover assembly comprises an O-ring for sealing an interface surface between edges of said top cover when screwing onto said base cylinder housing. 
 
     
     
       11. The TPMD of  claim 9  further wherein:
 said top cover further includes a transparent cover for transmitting a low pressure warning light as a visible light through the transparent cover when said LED is turned on in a low tire pressure tire condition.